Rosin is a hard, brittle, naturally occurring substance derived from the distillation of oil of turpentine, which is itself derived from pine trees. Rosin has been used for centuries to create friction between stringed instrument bow hairs and the strings of instruments like violins. Rosin is typically supplied in a small cake form that is rubbed onto the hairs of a bow in order to give the bow hairs enough tackiness to cause the instrument strings to vibrate when rubbed across the strings. It is the vibration of the strings that causes the sound of the instrument. For this invention, bow rosin is defined as any naturally derived gum, wood, or tall oil rosin which is applied to the strings of a bow in order to cause friction with the strings of an instrument and produce sound.
Rosin is primarily comprised of abietic acid, isomers of abietic acid, and numerous other naturally occurring compounds. Because it is naturally derived, and because of its organic acid chemical structure, rosin has at least five distinct drawbacks:    1. Rosin is hydrophilic and absorbs water. This causes the tackiness of the rosin to vary according to ambient humidity, which affects the sound of the instrument.    2. Rosin is susceptible to oxidation. Rosin becomes a fine powder, when applied to bow hairs. This powder has a high surface to volume ratio and rapidly reacts with ambient oxygen. As rosin oxidizes, it loses tack and essentially loses its effectiveness.    3. Rosin is a naturally occurring resin suspected of causing allergic reactions in susceptible people.    4. Rosin is primarily an organic acid and potentially corrosive. Rosin dust typically accumulates on the surface of the instrument and bow and can corrode the wood's varnish.    5. Rosin is very brittle and tends to break easily.
It is possible to slightly improve upon the properties of rosin and minimize some of these drawbacks by adding polymers to improve impact resistance, adding antioxidants to minimize oxidation, chemically reacting rosin by hydrogenation or esterification to minimize oxidation, and rosin can be neutralized with bases to minimize corrosion. However, none of these modifications, in whole or in combination, can significantly improve upon the properties of the bow rosin used today.